Uranium (U): Electron Configuration, Properties and Uses
Uranium (U): Electron Configuration, Properties and Uses
Electron configuration [Rn] 7s2 5f3 6d1 · f-block, actinide series · period 7 · Ar 238.03
Uranium data
- Atomic number
- 92
- Relative atomic mass
- 238.03
- Group
- – (actinide series)
- Period
- 7
- Block
- f
- Category
- Actinide
- Electron configuration
- [Rn] 7s2 5f3 6d1
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f3 6d1
- Electrons per shell
- 2, 8, 18, 32, 21, 9, 2 (K L M N O P Q)
- Valence electrons
- 2 (in the outer shell)
- Electronegativity (Pauling)
- 1.38
- First ionisation energy
- 6.194 eV
- Atomic radius (van der Waals)
- 240 pm
- State at room temperature
- Solid
- Melting point
- 1135 °C
- Boiling point
- 4131 °C
- Density
- 18.95 g/cm³
- Common oxidation states
- +6, +5, +4, +3
- Discovered
- 1789
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 8 · M 18 · N 32 · O 21 · P 9 · Q 2
Orbital diagram (outer electrons)
About uranium
Uranium, symbol U, is element number 92 in the periodic table. It belongs to the actinide series in period 7 (f-block), usually shown below the main table. Uranium was first discovered in 1789. It is named after the planet Uranus. Uranium is a solid at room temperature, melting at 1135 °C and boiling at 4131 °C.
Uranium electron configuration
The electron configuration of uranium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f3 6d1, or in short [Rn] 7s2 5f3 6d1. Its electrons occupy 7 shells: K = 2, L = 8, M = 18, N = 32, O = 21, P = 9, Q = 2. As an actinide, uranium fills the 5f subshell. Its outer 7s subshell holds 2 electrons; valence electrons for this series are not assigned by the usual group rule. This is an exception to the Aufbau rule: the usual filling order predicts [Rn] 7s2 5f4, but the 5f and 6d subshells are so close in energy that electrons occupy 6d. When it forms cations, electrons leave the outermost subshell first: U3+ = [Rn] 5f3.
Filling order: 1s2(2) → 2s2(4) → 2p6(10) → 3s2(12) → 3p6(18) → 4s2(20) → 3d10(30) → 4p6(36) → 5s2(38) → 4d10(48) → 5p6(54) → 6s2(56) → 4f14(70) → 5d10(80) → 6p6(86) → 7s2(88) → 5f3(91) → 6d1(92)
Uses of uranium
Well-known applications of uranium include fuel for nuclear power plants (U-235), depleted-uranium ballast, and uranyl acetate stain for electron microscopy.
Safety
Uranium is radioactive. Using, storing or transporting radioactive material requires a licence from the national regulator (BAPETEN in Indonesia). Always read the safety data sheet (SDS) before working with a chemical.
Other actinides
Frequently asked questions
What is the electron configuration of uranium?
The electron configuration of uranium (U, atomic number 92) is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f3 6d1, or [Rn] 7s2 5f3 6d1 in short. By shell: 2, 8, 18, 32, 21, 9, 2.
How many valence electrons does uranium have?
Uranium has 2 electrons in its outer shell. For lanthanides and actinides, valence electrons are not assigned by the usual group rule.
Which group and period is uranium in?
Uranium is in the actinide series, period 7, f-block.
What is the atomic mass of uranium?
The relative atomic mass of uranium is 238.03. Use it to calculate molar mass with the molar mass calculator.
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